PROJECT SUMMARY Project II. MicroRNAs in Anesthetic Cardioprotection (PI: Mingyu Liang) The goal of Project II is to test the hypothesis that miR-21 contributes to cardioprotection conferred by anesthetics in animal models and in human cardiomyocytes. MicroRNAs are endogenous small RNA molecules that regulate a wide range of cellular functions primarily through reducing the abundance of target proteins. MicroRNAs have been shown to be powerful regulators of cardiac development, injury, and remodeling. However, the role of microRNAs in anesthetic cardioprotection and its impairment by diabetic conditions remains unknown. We and other investigators have reported that microRNA miR-21 contributes to ischemic preconditioning of the heart and the kidney and to xenon-induced protection of the kidney. Importantly, we have obtained very exciting preliminary data strongly supporting an important role of miR-21 in isoflurane-induced cardioprotection and its impairment by diabetic conditions in animal models and in human cardiomyocytes generated from non-diabetic individual-derived induced pluripotent stem cells (iPSCs) (N-CM) or from a type 2 diabetic patient-derived iPSCs (T2-CM). Based on these novel findings, we propose in Aim 1 to use gene knockout or transgenesis to further examine the role of miR-21 in anesthetic cardioprotection in animal models and in possible restoration of anesthetic cardioprotection in models of type 2 diabetes. In Aim 2, we will translate the findings to human using patient-specific cardiomyocytes including N-CM and T2-CM. Finally, in Aim 3, we will investigate the molecular mechanisms involved by examining miR-21 target genes and their downstream pathways linked to mitochondrial function and mitochondrial permeability transition pore dysregulation as well as additional mechanistic pathways. Project II shares the central theme of the PPG, which is to investigate cellular mechanisms underlying anesthetic cardioprotection and its impairment by diabetic conditions. Project II will interact extensively with Projects I and III by studying shared mechanistic pathways leading to mitochondrial dysfunction and cell death. Results of Project II will be used to test, validate, and extend the mathematical models developed in Project III.